3 files changed, 95 insertions(+), 3 deletions(-)

M StreamPlayer/Source/MainViewController.m
M StreamPlayer/Source/ZANStreamPlayer.h
M StreamPlayer/Source/ZANStreamPlayer.m

@@ 48,6 48,14 @@ static NSString * const MVCSavedURLStringDefaultsKey = @"SavedURLString";
     }
 }
 
+- (void)streamPlayer:(ZANStreamPlayer *)player
+  didDecodeAudioData:(NSData *)data
+     withFramesCount:(NSUInteger)framesCount
+              format:(const AudioStreamBasicDescription *)format
+{
+    // cool
+}
+
 #pragma mark - Actions
 
 - (IBAction)_playPauseButtonPressed:(id)sender


@@ 58,7 66,7 @@ static NSString * const MVCSavedURLStringDefaultsKey = @"SavedURLString";
     
     if (!_player) {
         NSURL *url = [[NSURL alloc] initWithString:self.urlTextField.stringValue];
-        _player = [[ZANStreamPlayer alloc] initWithURL:url];
+        _player = [[ZANStreamPlayer alloc] initWithURL:url options:ZANStreamPlayerOptionInstallProcessingTap];
         _player.delegate = self;
     }
     

@@ 7,6 7,7 @@
 //
 
 #import <Foundation/Foundation.h>
+#import <CoreAudio/CoreAudioTypes.h>
 
 NS_ASSUME_NONNULL_BEGIN
 


@@ 18,19 19,34 @@ NS_ASSUME_NONNULL_BEGIN
 - (void)streamPlayerPlaybackStateDidChange:(ZANStreamPlayer *)player;
 - (void)streamPlayer:(ZANStreamPlayer *)player didEncounterError:(NSError *)error;
 
+// must initialize stream player with ZANStreamPlayerOptionInstallProcessingTap
+- (void)streamPlayer:(ZANStreamPlayer *)player
+  didDecodeAudioData:(NSData *)data
+     withFramesCount:(NSUInteger)framesCount
+              format:(const AudioStreamBasicDescription *)format;
+
 @end
 
 // -----------------------------------------------------------------------------
 
+typedef NS_OPTIONS(NSUInteger, ZANStreamPlayerOptions)
+{
+    ZANStreamPlayerOptionNone                   = 0,
+    ZANStreamPlayerOptionInstallProcessingTap   = (1 << 0),
+};
+
+// -----------------------------------------------------------------------------
+
 @interface ZANStreamPlayer : NSObject
 
 @property (nonatomic, weak) id<ZANStreamPlayerDelegate> delegate;
 
 @property (nonatomic, readonly) NSURL *url;
+@property (nonatomic, readonly) ZANStreamPlayerOptions options;
 @property (nonatomic, readonly, getter=isPlaying) BOOL playing;
 @property (nonatomic, readonly, getter=isStopped) BOOL stopped;
 
-- (instancetype)initWithURL:(NSURL *)url;
+- (instancetype)initWithURL:(NSURL *)url options:(ZANStreamPlayerOptions)options;
 
 - (void)play;
 - (void)pause;

@@ 44,6 44,14 @@ static void _ZANAudioQueueOutputCallback(void *clientData,
                                          AudioQueueRef audioQueue,
                                          AudioQueueBufferRef buffer);
 
+static void _ZANAudioQueueProcessingTapCallback(void *clientData,
+                                                AudioQueueProcessingTapRef tap,
+                                                UInt32 framesCount,
+                                                AudioTimeStamp *timestamp,
+                                                AudioQueueProcessingTapFlags *flags,
+                                                UInt32 *outFramesCount,
+                                                AudioBufferList *data);
+
 @interface ZANStreamPlayer () <NSURLSessionDataDelegate>
 
 @property (nonatomic, assign) ZANStreamPlaybackState playbackState;


@@ 58,6 66,8 @@ static void _ZANAudioQueueOutputCallback(void *clientData,
     AudioQueueRef                _audioQueue;
     AudioQueueBufferRef          _audioQueueBuffers[AUDIO_QUEUE_BUFFERS_COUNT];
     AudioStreamPacketDescription _packetDescriptions[MAX_PACKET_DESCRIPTIONS];
+    AudioQueueProcessingTapRef   _processingTap;
+    AudioStreamBasicDescription  _processingFormat;
     
     NSOperationQueue            *_inputQueue;
     BOOL                         _queueBuffersUsageStates[AUDIO_QUEUE_BUFFERS_COUNT];


@@ 73,11 83,12 @@ static void _ZANAudioQueueOutputCallback(void *clientData,
     AudioStreamBasicDescription  _audioStreamDescription;
 }
 
-- (instancetype)initWithURL:(NSURL *)url
+- (instancetype)initWithURL:(NSURL *)url options:(ZANStreamPlayerOptions)options
 {
     self = [super init];
     if (self) {
         _url = [url copy];
+        _options = options;
         
         _inputQueue = [[NSOperationQueue alloc] init];
         _inputQueue.maxConcurrentOperationCount = 1;


@@ 97,6 108,11 @@ static void _ZANAudioQueueOutputCallback(void *clientData,
     [self _closeAudioStream];
     [self _destroyAudioOutputQueue];
     
+    if (_processingTap) {
+        AudioQueueProcessingTapDispose(_processingTap);
+        _processingTap = NULL;
+    }
+    
     pthread_mutex_destroy(&_queueBuffersMutex);
     pthread_cond_destroy(&_queueBufferReadyCondition);
     


@@ 348,6 364,22 @@ static void _ZANAudioQueueOutputCallback(void *clientData,
                 break;
             }
         }
+        
+        // create processing tap, if requested
+        if (_options & ZANStreamPlayerOptionInstallProcessingTap) {
+            UInt32 maxFrames = 0;
+            status = AudioQueueProcessingTapNew(_audioQueue,
+                                                _ZANAudioQueueProcessingTapCallback,
+                                                (__bridge void *)self,
+                                                kAudioQueueProcessingTap_PostEffects,
+                                                &maxFrames,
+                                                &_processingFormat,
+                                                &_processingTap);
+            if (status != noErr) {
+                [self _logError:@"Failed to initialize processing tap (OSStatus = %d)", status];
+                break;
+            }
+        }
     } while (0);
     
     if (outError) {


@@ 579,6 611,23 @@ static void _ZANAudioQueueOutputCallback(void *clientData,
     pthread_mutex_unlock(&_queueBuffersMutex);
 }
 
+- (void)_handleTapCallbackFromTap:(AudioQueueProcessingTapRef)tap
+                  withFramesCount:(UInt32)inNumberFrames
+                   audioTimestamp:(AudioTimeStamp *)ioTimeStamp
+               processingTapFlags:(AudioQueueProcessingTapFlags *)flags
+                   outFramesCount:(UInt32 *)outNumberFrames
+                             data:(AudioBufferList *)ioData
+{
+    OSStatus status = AudioQueueProcessingTapGetSourceAudio(tap, inNumberFrames, ioTimeStamp, flags, outNumberFrames, ioData);
+    if (status != noErr) {
+        [self _logError:@"Faield to get source audio in processing tap callback (OSStatus = %d)", status];
+    } else {
+        AudioBuffer *buffer = &ioData->mBuffers[0];
+        NSData *audioData = [NSData dataWithBytesNoCopy:buffer->mData length:buffer->mDataByteSize freeWhenDone:NO];
+        [_delegate streamPlayer:self didDecodeAudioData:audioData withFramesCount:inNumberFrames format:&_processingFormat];
+    }
+}
+
 - (NSError *)_errorFromOSStatus:(OSStatus)status
 {
     NSError *error = nil;


@@ 661,4 710,23 @@ void _ZANAudioQueueOutputCallback(void *clientData, AudioQueueRef audioQueue, Au
     }
 }
 
+void _ZANAudioQueueProcessingTapCallback(void *clientData,
+                                         AudioQueueProcessingTapRef tap,
+                                         UInt32 framesCount,
+                                         AudioTimeStamp *timestamp,
+                                         AudioQueueProcessingTapFlags *flags,
+                                         UInt32 *outFramesCount,
+                                         AudioBufferList *data)
+{
+    @autoreleasepool {
+        ZANStreamPlayer *player = (__bridge ZANStreamPlayer *)clientData;
+        [player _handleTapCallbackFromTap:tap
+                          withFramesCount:framesCount
+                           audioTimestamp:timestamp
+                       processingTapFlags:flags
+                           outFramesCount:outFramesCount
+                                     data:data];
+    }
+}
+
 @end